400ex

42 pilot jet. I would use the needle out of the fmf kit if there is an adjustable one. Go one clip down(pointed end being bottom) from the middle slot. And a 160-165 main jet. You will have to remove the carb from the quad entirely. Take the float bowl off and change the pilot jet. It will have a flat tip head on it. Under a little plastic baffle. The 42 pilot jet will make the quad start up alot better when cold. While you have the bowl off change the main jet. It will be sticking out further then the pilot jet and be a hex headed jet. Then put the bowl back on and remove the top to get at the needle. Since your quad is an 04 your stock needle may already be adjustable. If it is just drop the clip on slot. If not use the fmf kit needle that should be adjustable. To get the needle out you gotta remove the 2 phillips screws down in the slide. They will be a real pain to put back in without a magnetic tip driver. You also have to remove the bigger phillips screw and swing the whole thing out of the way. Getting the bigger screw back lined up with the shaft can be alittle bit of a pain also. Good luck and ask alot of questions if you get stumped.